This invention relates to electrical connectors and, more particularly, to such connectors for terminating the exposed end of a stranded cable conductor into the body of the connector by means of a threaded fastener such as a setscrew.
Electrical terminal lug connectors for providing electrical and mechanical termination of a stripped stranded wire cable conductor are known and have been widely used in the art. These devices generally comprise a terminal lug body having a longitudinally extending conductor receiving bore therein and a threaded setscrew receiving bore therein which is perpendicular to the longitudinal axis of the conductor bore. The setscrew compressively engages the stranded wire bundle to complete the mechanical and electrical connection. Although these electrical connectors have been widely used in the art, they fail to consistently achieve good conductor holding ability and low resistance electrical connection characteristics particularly in environments having wide ambient temperature variations. For example, the industry has proposed a standard known in the art as the U/L 486B connector test which requires that the connection attain given mechanical and electrical specifications including specified performance in an elevated temperature heat cycle test. It has been found that many of these prior art electrical connectors fail to consistently attain such rigorous electrical and mechanical specifications. It has also been found that some of these devices tend to mechanically fail as the required torque specification is applied to the threaded fastener or setscrew.
Improvements in electrical connectors of the above-mentioned type are also known and have been widely used in the art. The improved devices are exemplified and discussed in U.S. Pat. No. 4,146,290 which discloses such an electrical terminal lug connector wherein an additional set of apertures or windows are provided along the side walls of the connector and extend inwardly into the body of the connector in a direction which is transverse to the axis of both the conductor receiving bore hole and the threaded setscrew receiving bore hole. These apertures or windows function to provide improved mechanical and electrical connections in that as the setscrew is torqued to the recommended setting, the wire strands are slightly bulged into the apertures or windows creating a relatively firm, low resistance connection. The present invention provides a further improvement in electrical terminal lugs and which has been found to attain the specifications mandated by the abovementioned industry standard.